MAJIEDT J paragraph 50 of that judgment is misconceived. The Supreme Court of Appeal held that no all-embracing definition of “abuse of process” has been formulated in our law. It said that in general, legal process is used properly when it is invoked for the vindication of rights or the enforcement of just claims and it is abused when it is diverted from its true course so as to serve extortion or oppression; or to exert pressure so as to achieve an improper end. The passage that “[p]urpose or motive, even a mischievous or malicious motive, is not in general a criterion for unlawfulness or invalidity”, is no authority at all for the proposition that ulterior motive on its own is recognised as an abuse of process giving rise to a self-standing defence to a substantive claim. Improper motive was merely regarded as a factor. [75] Lastly, Ascendis82 concerned an application for the revocation of a patent. The question was raised whether findings in a revocation application have a binding effect in a later action based on infringement. This case further raised questions of res judicata,83 issue estoppel and piecemeal litigation in patent disputes. The dictum of Khampepe J relied upon relates to the fact that abuse of process had not been pleaded and therefore no finding needed to be made in this regard. The passage cited is merely a repeat of a well-established principle. [76] I conclude by briefly saying something in general about the cases cited by the parties. These cases illustrate the fact that— (a) sometimes, motive is constitutive of the cause of action for example, in a malicious prosecution; (b) sometimes, the reason for the action is irrelevant, it is the legality of the action that counts for example, in an unlawful arrest; (c) sometimes, it is the abuse of the court’s processes that warrants sanction for example, in the case of Cassimjee;84 and 82 Ascendis above n 18. 83 That is, whether the substance of the matter has already been judged. 84 Cassimjee above n 53. 34